1. Field of the Invention
The present invention generally relates to control switches, and more particularly to a device intended for use as a light dimmer switch.
2. Description of the Prior Art
Power switches are manufactured in all shapes and sizes for a sundry of different purposes. The present application is directed to a particular power switch which, although intended for use as a light dimmer, could be used with motors and in other applications. Electrical switches of the type referred to herein generally consist of two or more wires for connection to an external power source, a pair of metal contacts connected to these wires, and a lever or button used to actuate the contacts between open and closed states.
There are several different types of light switches. These include knife switches, mercury switches, turnstile type switches, tumbler switches, push-button switches and electromagnetic switches, all familiar to those skilled in the art. A network of lights may be managed by a single rotary power switch having a plurality of contacts. For light dimming circuits, early switches incorporated a rheostat or potentiometer for regulating the power transmitted to the light bulb. Modern dimmers use a triac firing circuit which generates considerably less heat and power loss than the older potentiometer configuration, although a variable resistor is still employed to adjust the firing range of the triac.
Several problems arise in the manufacture, installation, and use of dimmer switches. One such problem occurs in slide-type dimmers. The slide knob extends outward from the internal mechanism of the switch, leaving an unsightly gap which peers inside the device. Also, a relatively expensive bearing system must be provided to insure smooth movement of the slide along its path. These difficulties are encountered in the fabrication of the device, and no presently available switches provide a simplified slide arrangement.
Another problem relates to quality control testing of the switches. Typically, light switches are held together by a metallic strap on the front of the switch which is fastened to a surrounding box on the backside of the switch. The moving parts of the switch, as well as the circuitry, cannot be tested until the back box is in place, thereby securing all of the mechanical and electrical components together. If, however, a particular unit should fail the test performed just before packing, then the entire unit must be disassembled (i.e., the box and strap removed), in order to determine the cause of the failure. If this problem arises frequently in a mass production setting, it results in a substantial increase in labor costs during manufacture.
The next complication occurs during installation of the switch. With several types of switches, it is impossible to tell whether the switch is in an "on" or "off" state. This creates a safety hazard during installation since an electrician or homeowner may install a switch which is closed, exposing the person to a live circuit. Even if the switch is marked as to on and off positions, the installer may not notice what state the switch is in during installation. At the present time, there are no safety features associated with the switches themselves which would overcome this problem.
The final difficulty concerns finding the light switch when the room is completely dark. Several switches have been manufactured which overcome this problem by actually placing a small bulb within the device, for example, within a translucent lever arm which actuates the switch. The main disadvantage to this type of switch, however, is that the bulb eventually burns out.
It would, therefore, be desirable and advantageous to devise a light dimming switch which would overcome the above-stated problems. The present invention does so by providing (1) a novel slide arrangement having an ultrathin profile, (2) a switch frame which holds the components together without attachment of the back box, (3) a unique air gap lever which prevents premature actuation of the switch, and (4) a novel light pipe which doubles as an actuator arm for full on-off.